A Trans-Impedance Amplifier (TIA) is an amplifier that converts current to voltage. A TIA can be used as part of a receiver for optical communication to convert electrical current pulse generated by a photodiode to a voltage signal for further processing. This is particularly useful due to the fact that the photo-current pulse output of the photodiode is relatively small and in need of amplification prior to being used in other circuits. Moreover, when used in connection with high data rateoptical communication systems, the time period of the photo current pulses get shorted and the TIA electrical bandwidth becomes important.
Unfortunately, designing an amplification circuit for a photodiode at a high data rate is not always straight forward. In particular, if a large resistor is connected across a feedback path of the amplifier, the photodiode's shunt capacitance will cause the amplifier bandwidth to decrease and in some cases may result in oscillations.
An equalization circuit is used to adjust a relative amplitude of frequency components of an electrical signal. For example, an equalization circuit in an optical communication system may adjust an electrical signal over the optical link such that a frequency response of the optical link is substantially flat over a specified range of frequency.